title: Flavone-catalyzed apoptosis in Scutellaria baicalensis.
abstract: In response to mechanical damage, roots of Scutellaria baicalensis undergo cell death within 24h. The flavone baicalein was identified as the factor regulating apoptosis in the damaged roots of S. baicalensis. Plant apoptosis is known to be triggered by oxidative damage of DNA through oxidative bursts, whereas baicalein causes apoptosis in Scutellaria cells by a copper-dependent oxidation of nuclear DNA without inducing an oxidative burst. S. baicalensis possesses an interesting system for quickly producing this apoptosis-inducing flavone in its cells. Intact Scutellaria cells contain little baicalein but store a large amount of baicalin (baicalein 7-O-β-D-glucuronide). Stress treatment of Scutellaria cells immediately initiates hydrolysis of baicalin by endogenous β-glucuronidase, and the resulting baicalein is immediately translocated to the nucleus, leading to apoptosis. Thus, S. baicalensis possesses a unique apoptosis-inducing system that is linked with metabolism of baicalin.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Motosuke
authors.initials: M
authors.lastname: Hirunuma
authors.forename: Yoshinari
authors.initials: Y
authors.lastname: Shoyama
authors.forename: Kaori
authors.initials: K
authors.lastname: Sasaki
authors.forename: Seiichi
authors.initials: S
authors.lastname: Sakamoto
authors.forename: Futoshi
authors.initials: F
authors.lastname: Taura
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Shoyama
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tanaka
authors.forename: Satoshi
authors.initials: S
authors.lastname: Morimoto
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D002384:Catalysis; D003300:Copper / Q000494:pharmacology; D004249:DNA Damage / Q000502:physiology; D044950:Flavanones / Q000737:chemistry / Q000494:pharmacology; D005419:Flavonoids / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D005966:Glucuronidase / Q000378:metabolism; D015394:Molecular Structure; D010084:Oxidation-Reduction; D018517:Plant Roots / Q000737:chemistry / Q000187:drug effects; D031364:Scutellaria baicalensis / Q000737:chemistry*
chemical_list: D044950:Flavanones; D005419:Flavonoids; C038044:baicalin; C006680:baicalein; D003300:Copper; D005966:Glucuronidase